The present invention relates generally to an body coil system for use with an open magnetic resonance (MR) magnet, that is, a magnet which generates a main magnetic field for MR imaging in a space which is accessible to a patient or other imaging subject, and is not enclosed within a magnet bore. More particularly, the invention pertains to a body coil system for use in connection with an open MR system.
Open MR imaging represents an innovation in the field of MR imaging. The configuration of an open MR system generally comprises magnet components that are positioned on opposite sides of an imaging space. One particularly useful design comprises two donut-shaped ring magnets. The two ring magnets are energized to provide a resultant field in the imaging space which comprises the static magnetic field for MR imaging. This configuration enables the positioning of an imaging subject more conveniently and more comfortably than the closed magnetic bore configuration. Specifically, the subject can enter the imaging space either by passing through the center of one of the ring magnets or can enter directly into the space between them. Also, the open magnet arrangement enables attendant physicians access to the subject to treat and closely monitor a subject while MR imaging is in progress.
If an interventional procedure is to be performed while a patient is in an MR imaging system, it is essential that the clinician have adequate access to the patient during the procedure. Also, the image quality must be sufficiently high enough to assist the clinician during an interventional procedure while imaging.
To allow access to the patient, current interventional MR imaging systems such as the GE SIGNA(trademark) SP employ flexible coils including an opening to provide access to the region being imaged and for both transmit and receive functions. While these coils provide adequate access to the patients, acquiring the image quality needed for use during interventional procedures is challenging due to inconsistent behavior and variable geometry of such coils. Examples of challenges include non-uniform images with reduced signal to noise in the region of interest.
In conventional MR scanners high image quality is frequently obtained by employing a large transmit coil for the creation of the MR signal and smaller surface coils for the detection of the MR signal. This combination provides optimal signal-to-noise ratios, particularly when the surface coil is a multi-coil array. Unfortunately, it has not been possible to use such a coil combination in interventional procedures because current body coil designs employ structures such as inductive elements and rf shields which prevent adequate access to the patient.
Thus, there is a need for an imaging coil system that provides both high image quality while at the same time providing access to the patient.
A rotating body coil assembly for use with an open MR magnet for imaging at least a portion of a subject comprises a resonant structure configured to rotate about the subject and to permit access to the subject during imaging.
A rotating body coil assembly for use with an open MR magnet that comprises a pair of main magnet components positioned on opposing sides of an imaging space disposed to receive at least a portion of a subject for imaging. The body coil assembly comprises first and second end ring assemblies positioned on opposing sides of the imaging space. The first and second end ring assemblies are each configured to energize the body coil assembly. A plurality of element assemblies are disposed between and connecting the first and second end ring assemblies for providing structural support and electrical isolation of the body coil assembly. A base assembly is coupled to the first and second end ring assemblies and at least one of the element assemblies. The base assembly is adapted to rotate the first and second end ring assemblies in cooperation with the plurality of element assemblies about the portion of the subject while the portion of the subject is inside the imaging space for permitting access to the subject during imaging.